On and on Coeurl prowled. The black, moonless, almost starless night yielded reluctantly before a grim reddish dawn that crept up from his left. It was a vague light that gave no sense of approaching warmth. It slowly revealed a nightmare landscape.

Jagged black rock and a black, lifeless plain took form around him. A pale red sun peered above the grotesque horizon. Fingers of light probed among the shadows. And still there was no sign of the family of id creatures that he had been trailing now for nearly a hundred days.

He stopped finally, chilled by the reality. His great forelegs twitched with a shuddering movement that arched every razor-sharp claw. The thick tentacles that grew from his shoulders undulated tautly. He twisted his great cat head from side to side, while the hair like tendrils that formed each ear vibrated frantically, testing every vagrant breeze, every throb in the ether.

There was no response. He felt no swift tingling along his intricate nervous system. There was no suggestion anywhere of the presence of the id creatures, his only source of food on this desolate planet. Hopelessly, Coeurl crouched, an enormous catlike figure silhouetted against the dim, reddish sky line, like a distorted etching of a black tiger in a shadow world. What dismayed him was the fact that he had lost touch. He possessed sensory equipment that could normally detect organic id miles away. He recognized that he was no longer normal. His overnight failure to maintain contact indicated a physical breakdown. This was the deadly sickness he had heard about. Seven times in the past century he had found coeurla, too weak to move, their otherwise immortal bodies emaciated and doomed for lack of food. Eagerly, then, he had smashed their unresisting bodies, and taken what little id was still keeping them alive.

Coeurl shivered with excitement, remembering those meals. Then he snarled audibly, a defiant sound that quavered on the air, echoed and re-echoed among the rocks, and shuddered back along his nerves. It was an instinctive expression of his will to live.

And then, abruptly, he stiffened.

High above the distant horizon he saw a tiny glowing spot. It came nearer. It grew rapidly, enormously, into a metal ball. It became a vast, round ship. The great globe, shining like polished silver, hissed by above Coeurl, slowing visibly. It receded over a black line of hills to the right, hovered almost motionless for a second, then sank down out of sight.

Coeurl exploded from his startled immobility. With tigerish speed, he raced down among the rocks. His round, black eyes burned with agonized desire. His ear tendrils, despite their diminished powers, vibrated a message of id in such quantities that his body felt sick with the pangs of his hunger.

The distant sun, pinkish now, was high in the purple and black sky when he crept up behind a mass of rock and gazed from its shadows at the ruins of the city that sprawled below him. The silvery ship, in spite of its size, looked small against the great spread of the deserted, crumbling city. Yet about the ship was a leashed aliveness, a dynamic quiescence that, after a moment, made it stand out, dominating the foreground. It rested in a cradle made by its own weight in the rocky, resisting plain which began abruptly at the outskirts of the dead metropolis.

Coeurl gazed at the two-legged beings who had come from inside the ship. They stood in little groups near the bottom of an escalator that had been lowered from a brilliantly lighted opening a hundred feet above the ground. His throat thickened with the immediacy of his need. His brain grew dark with the impulse to charge out and smash these flimsy-looking creatures whose bodies emitted the id vibrations.

Mists of memory stopped that impulse when it was still only electricity surging through his muscles. It was a memory of the distant past of his own race, of machines that could destroy, of energies potent beyond all the powers of his own body. The remembrance poisoned the reservoirs of his strength. He had time to see that the beings wore something over their real bodies, a shimmering transparent material that glittered and flashed in the rays of the sun.

Cunning came, understanding of the presence of these creatures. This, Coeurl reasoned for the first time, was a scientific expedition from another star. Scientists would investigate, and not destroy. Scientists would refrain from killing him if he did not attack. Scientists in their way were fools.

Bold with his hunger, he emerged into the open. He saw the creatures become aware of him. They turned and stared. The three nearest him moved slowly back toward larger groups. One individual, the smallest of his group, detached a dull metal rod from a sheath at his side, and held it casually in one hand.

Coeurl was alarmed by the action, but he loped on. It was too late to turn back.